Description

STS Specialized Tactical Systems SX3 Stripped Billet Lower Receiver AR15

Upgrade your AR-15 build with the STS Specialized Tactical Systems SX3 Stripped Billet Lower Receiver, a high-performance foundation engineered for serious shooters. CNC-machined from a solid block of aircraft-grade billet aluminum, the SX3 delivers exceptional rigidity, tight tolerances, and enhanced aesthetics compared to standard forged lowers.

Designed to be multi-caliber compatible, this stripped lower receiver supports .223 Remington, 5.56 NATO, and other common AR-15 calibers, making it a versatile choice for both tactical builds and competitive shooting setups.

These lowers can be shipped to CALIFORNIA Precision machined by STS, the SX3 stripped lower is a bare bones version of the SX3 complete. This lower is machined from a solid block of T6 51 7075 billet aluminum.

STS SX3 Stripped Billet Lower Receiver – AR-15 Platform

Precision-Machined Billet Aluminum | Multi-Caliber | Performance-Driven Design

Take your custom AR build to the next level with the STS SX3 Stripped Billet Lower Receiver, engineered for superior strength, precision, and reliability. This multi-caliber billet lower is CNC-machined from 7075-T6 aircraft-grade aluminum, delivering unmatched structural integrity and a premium finish that surpasses standard forged lowers.

With a flared magwell for faster reloads, integrated oversized trigger guard for gloved operation, and sleek machined lines, the SX3 lower is both tactical and ergonomic. It’s built to MIL-SPEC standards, ensuring compatibility with all standard AR-15 upper receivers and parts.

Whether you’re crafting a top-tier .223 Rem, 5.56 NATO, or custom-caliber AR-15, the STS SX3 is the billet foundation trusted by serious builders.

Key Features:

• Billet-Machined Aluminum – Crafted from a solid block for improved strength and precision

• AR-15 Platform Compatibility – Accepts all standard AR-15 upper receivers and components

• Multi-Caliber Marked – Ideal for .223/5.56 or custom-caliber AR builds

• Flared Magwell – Facilitates faster magazine changes

• Enhanced Trigger Guard – Integrated and oversized for gloved use

• Tight Tolerances – CNC precision ensures a snug, wobble-free upper fit

• Stylish Machined Lines – Adds custom aesthetic and improved grip surfaces

Ideal For:

• Custom AR-15 rifle or pistol builds

• Shooters demanding tight fitment, accuracy, and premium machining

• Builders seeking billet quality over standard forged lowers

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